diff --git a/index.js b/index.js
index 2db53a1..82a7ac0 100644
--- a/index.js
+++ b/index.js
@@ -8,6 +8,7 @@ const fs = BB.promisifyAll(require('graceful-fs'))
 const path = require('path')
 const rimraf = BB.promisify(require('rimraf'))
 const lifecycle = require('npm-lifecycle')
+const lockVerify = require('lock-verify')
 
 module.exports = main
 
@@ -32,7 +33,20 @@ function main (opts) {
     if (!pkg._shrinkwrap || !pkg._shrinkwrap.lockfileVersion) {
       throw new Error(`cipm can only install packages with an existing package-lock.json or npm-shrinkwrap.json with lockfileVersion >= 1. Run an install with npm@5 or later to generate it, then try again.`)
     }
-
+    return lockVerify(prefix).then(result => {
+      if (result.status) {
+        result.warnings.forEach(w => console.error('Warning:', w))
+      } else {
+        throw new Error(
+          'cipm can only install packages when your package.json and package-lock.json or ' +
+          'npm-shrinkwrap.json are in sync. Please update your lock file with `npm install` ' +
+          'before continuing.\n\n' +
+          result.warnings.map(w => 'Warning: ' + w).join('\n') + '\n' +
+          result.errors.join('\n') + '\n'
+        )
+      }
+    })
+  }).tap(pkg => {
     return rimraf(nodeModulesPath)
   }).tap(pkg => {
     return runScript('preinstall', pkg, prefix)
diff --git a/package-lock.json b/package-lock.json
index 96c74f2..17ec7d6 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -4,6 +4,16 @@
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
+    "@iarna/cli": {
+      "version": "1.2.0",
+      "resolved": "https://registry.npmjs.org/@iarna/cli/-/cli-1.2.0.tgz",
+      "integrity": "sha512-ukITQAqVs2n9HGmn3car/Ir7d3ta650iXhrG7pjr3EWdFmJuuOVWgYsu7ftsSe5VifEFFhjxVuX9+8F7L8hwcA==",
+      "requires": {
+        "signal-exit": "3.0.2",
+        "update-notifier": "2.2.0",
+        "yargs": "8.0.2"
+      }
+    },
     "JSONStream": {
       "version": "1.3.1",
       "resolved": "https://registry.npmjs.org/JSONStream/-/JSONStream-1.3.1.tgz",
@@ -86,6 +96,14 @@
       "integrity": "sha1-SlKCrBZHKek2Gbz9OtFR+BfOkfU=",
       "dev": true
     },
+    "ansi-align": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/ansi-align/-/ansi-align-2.0.0.tgz",
+      "integrity": "sha1-w2rsy6VjuJzrVW82kPCx2eNUf38=",
+      "requires": {
+        "string-width": "2.0.0"
+      }
+    },
     "ansi-escapes": {
       "version": "1.4.0",
       "resolved": "https://registry.npmjs.org/ansi-escapes/-/ansi-escapes-1.4.0.tgz",
@@ -100,8 +118,7 @@
     "ansi-styles": {
       "version": "2.2.1",
       "resolved": "https://registry.npmjs.org/ansi-styles/-/ansi-styles-2.2.1.tgz",
-      "integrity": "sha1-tDLdM1i2NM914eRmQ2gkBTPB3b4=",
-      "dev": true
+      "integrity": "sha1-tDLdM1i2NM914eRmQ2gkBTPB3b4="
     },
     "aproba": {
       "version": "1.1.2",
@@ -251,6 +268,48 @@
         "hoek": "2.16.3"
       }
     },
+    "boxen": {
+      "version": "1.2.1",
+      "resolved": "https://registry.npmjs.org/boxen/-/boxen-1.2.1.tgz",
+      "integrity": "sha1-DxHn/jRO25OXl3/BPt5/ZNlWSB0=",
+      "requires": {
+        "ansi-align": "2.0.0",
+        "camelcase": "4.1.0",
+        "chalk": "2.1.0",
+        "cli-boxes": "1.0.0",
+        "string-width": "2.0.0",
+        "term-size": "1.2.0",
+        "widest-line": "1.0.0"
+      },
+      "dependencies": {
+        "ansi-styles": {
+          "version": "3.2.0",
+          "resolved": "https://registry.npmjs.org/ansi-styles/-/ansi-styles-3.2.0.tgz",
+          "integrity": "sha512-NnSOmMEYtVR2JVMIGTzynRkkaxtiq1xnFBcdQD/DnNCYPoEPsVJhM98BDyaoNOQIi7p4okdi3E27eN7GQbsUug==",
+          "requires": {
+            "color-convert": "1.9.0"
+          }
+        },
+        "chalk": {
+          "version": "2.1.0",
+          "resolved": "https://registry.npmjs.org/chalk/-/chalk-2.1.0.tgz",
+          "integrity": "sha512-LUHGS/dge4ujbXMJrnihYMcL4AoOweGnw9Tp3kQuqy1Kx5c1qKjqvMJZ6nVJPMWJtKCTN72ZogH3oeSO9g9rXQ==",
+          "requires": {
+            "ansi-styles": "3.2.0",
+            "escape-string-regexp": "1.0.5",
+            "supports-color": "4.4.0"
+          }
+        },
+        "supports-color": {
+          "version": "4.4.0",
+          "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-4.4.0.tgz",
+          "integrity": "sha512-rKC3+DyXWgK0ZLKwmRsrkyHVZAjNkfzeehuFWdGGcqGDTZFH73+RH6S/RDAAxl9GusSjZSUWYLmT9N5pzXFOXQ==",
+          "requires": {
+            "has-flag": "2.0.0"
+          }
+        }
+      }
+    },
     "brace-expansion": {
       "version": "1.1.7",
       "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.7.tgz",
@@ -350,6 +409,11 @@
         }
       }
     },
+    "capture-stack-trace": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/capture-stack-trace/-/capture-stack-trace-1.0.0.tgz",
+      "integrity": "sha1-Sm+gc5nCa7pH8LJJa00PtAjFVQ0="
+    },
     "caseless": {
       "version": "0.11.0",
       "resolved": "https://registry.npmjs.org/caseless/-/caseless-0.11.0.tgz",
@@ -371,7 +435,6 @@
       "version": "1.1.3",
       "resolved": "https://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
       "integrity": "sha1-qBFcVeSnAv5NFQq9OHKCKn4J/Jg=",
-      "dev": true,
       "requires": {
         "ansi-styles": "2.2.1",
         "escape-string-regexp": "1.0.5",
@@ -397,6 +460,11 @@
       "integrity": "sha1-Y/sRDcLOGoTcIfbZM0h20BCui2g=",
       "dev": true
     },
+    "cli-boxes": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/cli-boxes/-/cli-boxes-1.0.0.tgz",
+      "integrity": "sha1-T6kXw+WclKAEzWH47lCdplFocUM="
+    },
     "cli-cursor": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/cli-cursor/-/cli-cursor-1.0.2.tgz",
@@ -445,6 +513,19 @@
       "resolved": "https://registry.npmjs.org/code-point-at/-/code-point-at-1.1.0.tgz",
       "integrity": "sha1-DQcLTQQ6W+ozovGkDi7bPZpMz3c="
     },
+    "color-convert": {
+      "version": "1.9.0",
+      "resolved": "https://registry.npmjs.org/color-convert/-/color-convert-1.9.0.tgz",
+      "integrity": "sha1-Gsz5fdc5uYO/mU1W/sj5WFNkG3o=",
+      "requires": {
+        "color-name": "1.1.3"
+      }
+    },
+    "color-name": {
+      "version": "1.1.3",
+      "resolved": "https://registry.npmjs.org/color-name/-/color-name-1.1.3.tgz",
+      "integrity": "sha1-p9BVi9icQveV3UIyj3QIMcpTvCU="
+    },
     "color-support": {
       "version": "1.1.3",
       "resolved": "https://registry.npmjs.org/color-support/-/color-support-1.1.3.tgz",
@@ -491,6 +572,29 @@
         "typedarray": "0.0.6"
       }
     },
+    "configstore": {
+      "version": "3.1.1",
+      "resolved": "https://registry.npmjs.org/configstore/-/configstore-3.1.1.tgz",
+      "integrity": "sha512-5oNkD/L++l0O6xGXxb1EWS7SivtjfGQlRyxJsYgE0Z495/L81e2h4/d3r969hoPXuFItzNOKMtsXgYG4c7dYvw==",
+      "requires": {
+        "dot-prop": "4.2.0",
+        "graceful-fs": "4.1.11",
+        "make-dir": "1.0.0",
+        "unique-string": "1.0.0",
+        "write-file-atomic": "2.3.0",
+        "xdg-basedir": "3.0.0"
+      },
+      "dependencies": {
+        "dot-prop": {
+          "version": "4.2.0",
+          "resolved": "https://registry.npmjs.org/dot-prop/-/dot-prop-4.2.0.tgz",
+          "integrity": "sha512-tUMXrxlExSW6U2EXiiKGSBVdYgtV8qlHL+C10TsW4PURY/ic+eaysnSkwB4kA/mBlCyy/IKDJ+Lc3wbWeaXtuQ==",
+          "requires": {
+            "is-obj": "1.0.1"
+          }
+        }
+      }
+    },
     "console-control-strings": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/console-control-strings/-/console-control-strings-1.1.0.tgz",
@@ -813,6 +917,14 @@
         }
       }
     },
+    "create-error-class": {
+      "version": "3.0.2",
+      "resolved": "https://registry.npmjs.org/create-error-class/-/create-error-class-3.0.2.tgz",
+      "integrity": "sha1-Br56vvlHo/FKMP1hBnHUAbyot7Y=",
+      "requires": {
+        "capture-stack-trace": "1.0.0"
+      }
+    },
     "cross-spawn": {
       "version": "4.0.2",
       "resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-4.0.2.tgz",
@@ -831,6 +943,11 @@
         "boom": "2.10.1"
       }
     },
+    "crypto-random-string": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/crypto-random-string/-/crypto-random-string-1.0.0.tgz",
+      "integrity": "sha1-ojD2T1aDEOFJgAmUB5DsmVRbyn4="
+    },
     "currently-unhandled": {
       "version": "0.4.1",
       "resolved": "https://registry.npmjs.org/currently-unhandled/-/currently-unhandled-0.4.1.tgz",
@@ -917,6 +1034,11 @@
       "resolved": "https://registry.npmjs.org/decamelize/-/decamelize-1.2.0.tgz",
       "integrity": "sha1-9lNNFRSCabIDUue+4m9QH5oZEpA="
     },
+    "deep-extend": {
+      "version": "0.4.2",
+      "resolved": "https://registry.npmjs.org/deep-extend/-/deep-extend-0.4.2.tgz",
+      "integrity": "sha1-SLaZwn4zS/ifEIkr5DL25MfTSn8="
+    },
     "deep-is": {
       "version": "0.1.3",
       "resolved": "https://registry.npmjs.org/deep-is/-/deep-is-0.1.3.tgz",
@@ -998,6 +1120,11 @@
         "is-obj": "1.0.1"
       }
     },
+    "duplexer3": {
+      "version": "0.1.4",
+      "resolved": "https://registry.npmjs.org/duplexer3/-/duplexer3-0.1.4.tgz",
+      "integrity": "sha1-7gHdHKwO08vH/b6jfcCo8c4ALOI="
+    },
     "duplexify": {
       "version": "3.5.1",
       "resolved": "https://registry.npmjs.org/duplexify/-/duplexify-3.5.1.tgz",
@@ -1166,8 +1293,7 @@
     "escape-string-regexp": {
       "version": "1.0.5",
       "resolved": "https://registry.npmjs.org/escape-string-regexp/-/escape-string-regexp-1.0.5.tgz",
-      "integrity": "sha1-G2HAViGQqN/2rjuyzwIAyhMLhtQ=",
-      "dev": true
+      "integrity": "sha1-G2HAViGQqN/2rjuyzwIAyhMLhtQ="
     },
     "escope": {
       "version": "3.6.0",
@@ -1744,6 +1870,31 @@
         "pinkie-promise": "2.0.1"
       }
     },
+    "got": {
+      "version": "6.7.1",
+      "resolved": "https://registry.npmjs.org/got/-/got-6.7.1.tgz",
+      "integrity": "sha1-JAzQV4WpoY5WHcG0S0HHY+8ejbA=",
+      "requires": {
+        "create-error-class": "3.0.2",
+        "duplexer3": "0.1.4",
+        "get-stream": "3.0.0",
+        "is-redirect": "1.0.0",
+        "is-retry-allowed": "1.1.0",
+        "is-stream": "1.1.0",
+        "lowercase-keys": "1.0.0",
+        "safe-buffer": "5.0.1",
+        "timed-out": "4.0.1",
+        "unzip-response": "2.0.1",
+        "url-parse-lax": "1.0.0"
+      },
+      "dependencies": {
+        "get-stream": {
+          "version": "3.0.0",
+          "resolved": "https://registry.npmjs.org/get-stream/-/get-stream-3.0.0.tgz",
+          "integrity": "sha1-jpQ9E1jcN1VQVOy+LtsFqhdO3hQ="
+        }
+      }
+    },
     "graceful-fs": {
       "version": "4.1.11",
       "resolved": "https://registry.npmjs.org/graceful-fs/-/graceful-fs-4.1.11.tgz",
@@ -1786,11 +1937,15 @@
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/has-ansi/-/has-ansi-2.0.0.tgz",
       "integrity": "sha1-NPUEnOHs3ysGSa8+8k5F7TVBbZE=",
-      "dev": true,
       "requires": {
         "ansi-regex": "2.1.1"
       }
     },
+    "has-flag": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/has-flag/-/has-flag-2.0.0.tgz",
+      "integrity": "sha1-6CB68cx7MNRGzHC3NLXovhj4jVE="
+    },
     "has-unicode": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/has-unicode/-/has-unicode-2.0.1.tgz",
@@ -1885,6 +2040,11 @@
         "minimatch": "3.0.4"
       }
     },
+    "import-lazy": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/import-lazy/-/import-lazy-2.1.0.tgz",
+      "integrity": "sha1-BWmOPUXIjo1+nZLLBYTnfwlvPkM="
+    },
     "imurmurhash": {
       "version": "0.1.4",
       "resolved": "https://registry.npmjs.org/imurmurhash/-/imurmurhash-0.1.4.tgz",
@@ -1916,8 +2076,7 @@
     "ini": {
       "version": "1.3.4",
       "resolved": "https://registry.npmjs.org/ini/-/ini-1.3.4.tgz",
-      "integrity": "sha1-BTfLedr1m1mhpRff9wbIbsA5Fi4=",
-      "dev": true
+      "integrity": "sha1-BTfLedr1m1mhpRff9wbIbsA5Fi4="
     },
     "inquirer": {
       "version": "0.12.0",
@@ -2029,11 +2188,15 @@
         "xtend": "4.0.1"
       }
     },
+    "is-npm": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/is-npm/-/is-npm-1.0.0.tgz",
+      "integrity": "sha1-8vtjpl5JBbQGyGBydloaTceTufQ="
+    },
     "is-obj": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/is-obj/-/is-obj-1.0.1.tgz",
-      "integrity": "sha1-PkcprB9f3gJc19g6iW2rn09n2w8=",
-      "dev": true
+      "integrity": "sha1-PkcprB9f3gJc19g6iW2rn09n2w8="
     },
     "is-path-cwd": {
       "version": "1.0.0",
@@ -2065,6 +2228,11 @@
       "integrity": "sha1-V/4cTkhHTt1lsJkR8msc1Ald2oQ=",
       "dev": true
     },
+    "is-redirect": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/is-redirect/-/is-redirect-1.0.0.tgz",
+      "integrity": "sha1-HQPd7VO9jbDzDCbk+V02/HyH3CQ="
+    },
     "is-regex": {
       "version": "1.0.4",
       "resolved": "https://registry.npmjs.org/is-regex/-/is-regex-1.0.4.tgz",
@@ -2083,6 +2251,11 @@
         "tryit": "1.0.3"
       }
     },
+    "is-retry-allowed": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/is-retry-allowed/-/is-retry-allowed-1.1.0.tgz",
+      "integrity": "sha1-EaBgVotnM5REAz0BJaYaINVk+zQ="
+    },
     "is-stream": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/is-stream/-/is-stream-1.1.0.tgz",
@@ -2239,6 +2412,14 @@
         "is-buffer": "1.1.5"
       }
     },
+    "latest-version": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/latest-version/-/latest-version-3.1.0.tgz",
+      "integrity": "sha1-ogU4P+oyKzO1rjsYq+4NwvNW7hU=",
+      "requires": {
+        "package-json": "4.0.1"
+      }
+    },
     "lazy-cache": {
       "version": "1.0.4",
       "resolved": "https://registry.npmjs.org/lazy-cache/-/lazy-cache-1.0.4.tgz",
@@ -2290,6 +2471,23 @@
         "path-exists": "3.0.0"
       }
     },
+    "lock-verify": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/lock-verify/-/lock-verify-1.1.0.tgz",
+      "integrity": "sha512-Y/3Od84gH3UpPimEgmXYY5WLyOhlHGDiajJY3e7ZQdgvrBAIjUc+7dFohI6PF336zfGH5MTz6BuJ0JzgI62Y7A==",
+      "requires": {
+        "@iarna/cli": "1.2.0",
+        "npm-package-arg": "5.1.2",
+        "semver": "5.4.1"
+      },
+      "dependencies": {
+        "semver": {
+          "version": "5.4.1",
+          "resolved": "https://registry.npmjs.org/semver/-/semver-5.4.1.tgz",
+          "integrity": "sha512-WfG/X9+oATh81XtllIo/I8gOiY9EXRdv1cQdyykeXK17YcUW3EXUAi2To4pcH6nZtJPr7ZOpM5OMyWJZm+8Rsg=="
+        }
+      }
+    },
     "lodash": {
       "version": "4.17.4",
       "resolved": "https://registry.npmjs.org/lodash/-/lodash-4.17.4.tgz",
@@ -2349,6 +2547,11 @@
         "signal-exit": "3.0.2"
       }
     },
+    "lowercase-keys": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/lowercase-keys/-/lowercase-keys-1.0.0.tgz",
+      "integrity": "sha1-TjNms55/VFfjXxMkvfb4jQv8cwY="
+    },
     "lru-cache": {
       "version": "4.0.2",
       "resolved": "https://registry.npmjs.org/lru-cache/-/lru-cache-4.0.2.tgz",
@@ -2358,6 +2561,14 @@
         "yallist": "2.1.2"
       }
     },
+    "make-dir": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/make-dir/-/make-dir-1.0.0.tgz",
+      "integrity": "sha1-l6ARdR6R3YfPre9Ygy67BJNt6Xg=",
+      "requires": {
+        "pify": "2.3.0"
+      }
+    },
     "make-fetch-happen": {
       "version": "2.5.0",
       "resolved": "https://registry.npmjs.org/make-fetch-happen/-/make-fetch-happen-2.5.0.tgz",
@@ -4491,6 +4702,17 @@
         "p-limit": "1.1.0"
       }
     },
+    "package-json": {
+      "version": "4.0.1",
+      "resolved": "https://registry.npmjs.org/package-json/-/package-json-4.0.1.tgz",
+      "integrity": "sha1-iGmgQBJTZhxMTKPabCEh7VVfXu0=",
+      "requires": {
+        "got": "6.7.1",
+        "registry-auth-token": "3.3.1",
+        "registry-url": "3.1.0",
+        "semver": "5.3.0"
+      }
+    },
     "pacote": {
       "version": "6.0.1",
       "resolved": "https://registry.npmjs.org/pacote/-/pacote-6.0.1.tgz",
@@ -4729,6 +4951,11 @@
       "integrity": "sha1-IZMqVJ9eUv/ZqCf1cOBL5iqX2lQ=",
       "dev": true
     },
+    "prepend-http": {
+      "version": "1.0.4",
+      "resolved": "https://registry.npmjs.org/prepend-http/-/prepend-http-1.0.4.tgz",
+      "integrity": "sha1-1PRWKwzjaW5BrFLQ4ALlemNdxtw="
+    },
     "process-nextick-args": {
       "version": "1.0.7",
       "resolved": "https://registry.npmjs.org/process-nextick-args/-/process-nextick-args-1.0.7.tgz",
@@ -4809,6 +5036,24 @@
       "integrity": "sha1-51vV9uJoEioqDgvaYwslUMFmUCw=",
       "dev": true
     },
+    "rc": {
+      "version": "1.2.1",
+      "resolved": "https://registry.npmjs.org/rc/-/rc-1.2.1.tgz",
+      "integrity": "sha1-LgPo5C7kULjLPc5lvhv4l04d/ZU=",
+      "requires": {
+        "deep-extend": "0.4.2",
+        "ini": "1.3.4",
+        "minimist": "1.2.0",
+        "strip-json-comments": "2.0.1"
+      },
+      "dependencies": {
+        "minimist": {
+          "version": "1.2.0",
+          "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
+          "integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ="
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@@ -4872,6 +5117,23 @@
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+      "resolved": "https://registry.npmjs.org/registry-auth-token/-/registry-auth-token-3.3.1.tgz",
+      "integrity": "sha1-+w0yie4Nmtosu1KvXf5mywcNMAY=",
+      "requires": {
+        "rc": "1.2.1",
+        "safe-buffer": "5.0.1"
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+    "registry-url": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/registry-url/-/registry-url-3.1.0.tgz",
+      "integrity": "sha1-PU74cPc93h138M+aOBQyRE4XSUI=",
+      "requires": {
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       "resolved": "https://registry.npmjs.org/repeat-string/-/repeat-string-1.6.1.tgz",
@@ -5031,11 +5293,32 @@
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       "integrity": "sha1-myzl094C0XxgEq0yaqa00M9U+U8="
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+    "semver-diff": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/semver-diff/-/semver-diff-2.1.0.tgz",
+      "integrity": "sha1-S7uEN8jTfksM8aaP1ybsbWRdbTY=",
+      "requires": {
+        "semver": "5.3.0"
+      }
+    },
     "set-blocking": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/set-blocking/-/set-blocking-2.0.0.tgz",
       "integrity": "sha1-BF+XgtARrppoA93TgrJDkrPYkPc="
     },
+    "shebang-command": {
+      "version": "1.2.0",
+      "resolved": "https://registry.npmjs.org/shebang-command/-/shebang-command-1.2.0.tgz",
+      "integrity": "sha1-RKrGW2lbAzmJaMOfNj/uXer98eo=",
+      "requires": {
+        "shebang-regex": "1.0.0"
+      }
+    },
+    "shebang-regex": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/shebang-regex/-/shebang-regex-1.0.0.tgz",
+      "integrity": "sha1-2kL0l0DAtC2yypcoVxyxkMmO/qM="
+    },
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       "resolved": "https://registry.npmjs.org/shelljs/-/shelljs-0.7.8.tgz",
@@ -5342,14 +5625,12 @@
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       "resolved": "https://registry.npmjs.org/strip-json-comments/-/strip-json-comments-2.0.1.tgz",
-      "integrity": "sha1-PFMZQukIwml8DsNEhYwobHygpgo=",
-      "dev": true
+      "integrity": "sha1-PFMZQukIwml8DsNEhYwobHygpgo="
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     "supports-color": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-2.0.0.tgz",
-      "integrity": "sha1-U10EXOa2Nj+kARcIRimZXp3zJMc=",
-      "dev": true
+      "integrity": "sha1-U10EXOa2Nj+kARcIRimZXp3zJMc="
     },
     "table": {
       "version": "3.8.3",
@@ -5478,6 +5759,45 @@
         }
       }
     },
+    "term-size": {
+      "version": "1.2.0",
+      "resolved": "https://registry.npmjs.org/term-size/-/term-size-1.2.0.tgz",
+      "integrity": "sha1-RYuDiH8oj8Vtb/+/rSYuJmOO+mk=",
+      "requires": {
+        "execa": "0.7.0"
+      },
+      "dependencies": {
+        "cross-spawn": {
+          "version": "5.1.0",
+          "resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-5.1.0.tgz",
+          "integrity": "sha1-6L0O/uWPz/b4+UUQoKVUu/ojVEk=",
+          "requires": {
+            "lru-cache": "4.0.2",
+            "shebang-command": "1.2.0",
+            "which": "1.2.14"
+          }
+        },
+        "execa": {
+          "version": "0.7.0",
+          "resolved": "https://registry.npmjs.org/execa/-/execa-0.7.0.tgz",
+          "integrity": "sha1-lEvs00zEHuMqY6n68nrVpl/Fl3c=",
+          "requires": {
+            "cross-spawn": "5.1.0",
+            "get-stream": "3.0.0",
+            "is-stream": "1.1.0",
+            "npm-run-path": "2.0.2",
+            "p-finally": "1.0.0",
+            "signal-exit": "3.0.2",
+            "strip-eof": "1.0.0"
+          }
+        },
+        "get-stream": {
+          "version": "3.0.0",
+          "resolved": "https://registry.npmjs.org/get-stream/-/get-stream-3.0.0.tgz",
+          "integrity": "sha1-jpQ9E1jcN1VQVOy+LtsFqhdO3hQ="
+        }
+      }
+    },
     "text-extensions": {
       "version": "1.5.0",
       "resolved": "https://registry.npmjs.org/text-extensions/-/text-extensions-1.5.0.tgz",
@@ -5505,6 +5825,11 @@
         "xtend": "4.0.1"
       }
     },
+    "timed-out": {
+      "version": "4.0.1",
+      "resolved": "https://registry.npmjs.org/timed-out/-/timed-out-4.0.1.tgz",
+      "integrity": "sha1-8y6srFoXW+ol1/q1Zas+2HQe9W8="
+    },
     "tmatch": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/tmatch/-/tmatch-3.1.0.tgz",
@@ -5686,6 +6011,42 @@
         "imurmurhash": "0.1.4"
       }
     },
+    "unique-string": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/unique-string/-/unique-string-1.0.0.tgz",
+      "integrity": "sha1-nhBXzKhRq7kzmPizOuGHuZyuwRo=",
+      "requires": {
+        "crypto-random-string": "1.0.0"
+      }
+    },
+    "unzip-response": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/unzip-response/-/unzip-response-2.0.1.tgz",
+      "integrity": "sha1-0vD3N9FrBhXnKmk17QQhRXLVb5c="
+    },
+    "update-notifier": {
+      "version": "2.2.0",
+      "resolved": "https://registry.npmjs.org/update-notifier/-/update-notifier-2.2.0.tgz",
+      "integrity": "sha1-G1g3z5DAc22IYncytmHBOPht5y8=",
+      "requires": {
+        "boxen": "1.2.1",
+        "chalk": "1.1.3",
+        "configstore": "3.1.1",
+        "import-lazy": "2.1.0",
+        "is-npm": "1.0.0",
+        "latest-version": "3.1.0",
+        "semver-diff": "2.1.0",
+        "xdg-basedir": "3.0.0"
+      }
+    },
+    "url-parse-lax": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/url-parse-lax/-/url-parse-lax-1.0.0.tgz",
+      "integrity": "sha1-evjzA2Rem9eaJy56FKxovAYJ2nM=",
+      "requires": {
+        "prepend-http": "1.0.4"
+      }
+    },
     "user-home": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/user-home/-/user-home-2.0.0.tgz",
@@ -6056,6 +6417,26 @@
         "string-width": "2.0.0"
       }
     },
+    "widest-line": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/widest-line/-/widest-line-1.0.0.tgz",
+      "integrity": "sha1-DAnIXCqUaD0Nfq+O4JfVZL8OEFw=",
+      "requires": {
+        "string-width": "1.0.2"
+      },
+      "dependencies": {
+        "string-width": {
+          "version": "1.0.2",
+          "resolved": "https://registry.npmjs.org/string-width/-/string-width-1.0.2.tgz",
+          "integrity": "sha1-EYvfW4zcUaKn5w0hHgfisLmxB9M=",
+          "requires": {
+            "code-point-at": "1.1.0",
+            "is-fullwidth-code-point": "1.0.0",
+            "strip-ansi": "3.0.1"
+          }
+        }
+      }
+    },
     "window-size": {
       "version": "0.1.0",
       "resolved": "https://registry.npmjs.org/window-size/-/window-size-0.1.0.tgz",
@@ -6113,6 +6494,21 @@
         "mkdirp": "0.5.1"
       }
     },
+    "write-file-atomic": {
+      "version": "2.3.0",
+      "resolved": "https://registry.npmjs.org/write-file-atomic/-/write-file-atomic-2.3.0.tgz",
+      "integrity": "sha512-xuPeK4OdjWqtfi59ylvVL0Yn35SF3zgcAcv7rBPFHVaEapaDr4GdGgm3j7ckTwH9wHL7fGmgfAnb0+THrHb8tA==",
+      "requires": {
+        "graceful-fs": "4.1.11",
+        "imurmurhash": "0.1.4",
+        "signal-exit": "3.0.2"
+      }
+    },
+    "xdg-basedir": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/xdg-basedir/-/xdg-basedir-3.0.0.tgz",
+      "integrity": "sha1-SWsswQnsqNus/i3HK2A8F8WHCtQ="
+    },
     "xtend": {
       "version": "4.0.1",
       "resolved": "https://registry.npmjs.org/xtend/-/xtend-4.0.1.tgz",
diff --git a/package.json b/package.json
index 63eae28..f76e6ba 100644
--- a/package.json
+++ b/package.json
@@ -35,6 +35,7 @@
   "dependencies": {
     "bluebird": "^3.5.0",
     "graceful-fs": "^4.1.11",
+    "lock-verify": "^1.1.0",
     "npm-lifecycle": "^1.0.0",
     "npm-package-arg": "^5.1.2",
     "npmlog": "^4.1.2",